Optical Phased Arrays Laser Radar System And Performance Analysis

Laser radars are widely used in target detecting, tracking, aiming and imaging recognition because its extremely high resolution in frequency domain, space domain and time domain. From scanning mode, the laser radar system experienced mechanical scanning mode and non-scanned mode. The Optical phased arrays (OPA) laser radar system has high response speed and controlling precision, besides, the OPA laser radar system has flexibility in programmable scanning mode. The OPA laser radar is one of the most important developmental directions of the laser radar.In this paper, the OPA technology and the OPA laser radar are summarized. The most important device of the OPA laser radar is the optical phased arrays, we introduced the binary optics device---Dammann grating into the OPA laser radar system design to solve the problem of low imaging speed caused by the long response time of the OPA device. This method can increase the imaging speed of the OPA laser radar system.The performance of the OPA laser radar system which we designed was studied. The imaging speed of the OPA laser radar system can reach 16~24 Hz when the scanning spots array is 25×50per frame. The detecting range is about 1.52km and the range resolution is about1.5m ~ 1.95m . The field of view angle is 10×10 and the angle resolution is about 0.67mrad . The detecting area is 3927m 2at the distance of one kilometer. The detecting range of the system we designed is larger than the non-scanned laser radar and the imaging speed is larger than the mechanical scanning laser radar. We designed the optical phased control scheme based on the experimental conditions in existence.In addition, we built the theoretical model of the transmit system. The simulation result of the beam scanning was computed by MATLAB. We studied the inhomogeneity of the emitting spots: the light intensity of exit spots is homogeneous and the scanning image is electronically programmable controlled. The results indicate that the scheme of transmit system which is composed of Dammann grating and OPA is practicable, the light intensity's inhomogeneity is about 2% which satisfied the requirement of the laser radar system. The system can be implemented with the present device hopefully.